The invention herein is directed to a new and improved nebulizer for converting liquid into an aerosol. The nebulizer herein is particularly suited for medical applications, although may be useful in other applications wherein it is desirable to mix liquid with a gas.
Nebulizers are pneumatic devices which are designed to break up liquid medication into small particles and to entrain the small liquid particles in a stream of air or gas, which air or gas provides an aerosol for inhalation therapy in the treatment of respiratory system disorders. It is important during inhalation therapy that there be a sufficient quantity and proper formation of aerosol provided by the nebulizer. If the particles or droplets of the liquid medication are too fine, they are not likely to be retained in the respiratory track but will, to a great extent, be exhaled. If the particles are too large, they will likely be deposited on the upper reaches of the respiratory system, such as the trachea and the upper tracheal-bronchial tree, thereby leaving the rest of the system untreated. It is also important that the aerosol be delivered to the patient in a smooth, uniform manner.
A variety of nebulizers are commercially available. Many of such commercially available nebulizers are referred to as hand-held nebulizers. Such hand-held nebulizers are designed for being held by the patient receiving inhalation therapy treatment. The nebulizers can be for repeated use after sterilization or may be disposable. Generally, the disposable nebulizers are constructed of plastic. In many single use or individual patient hand-held nebulizers, the nebulizer is a relatively small design, generally about three inches long and designed to hold about 10 cc's of liquid medication or less.
A drawback with the commercially available nebulizers is that they do not utilize the entire volume of liquid medication. That is, as the volume of the medication decreases in the reservoir of the nebulizer below the volume necessary to maintain the syphon action, the syphon action stops, leaving an unnecessarily large amount of medication in the reservoir. In such operations, the attendant may add additional medication or will dispose of the nebulizer. When the nebulizer is removed from the inhalation circuit, some of the liquid medication remains in the nebulizer. Either the addition of additional medication or disposing of the nebulizer with liquid medication remaining in the bowl are undesirable and costly due to the expense of the liquid medication. It would be desirable to have a nebulizer which can substantially utilize all of the liquid medication in the nebulizer or at least a substantial volume of such liquid medication.
In addition to the above drawback, the hand-held nebulizers are sufficiently small that it is difficult to keep the nebulizers oriented in a particular direction. That is, during use the hand-held nebulizer may assume various positions such as lying on its side or being angled in a variety of different positions by the patient holding the nebulizer. For example, it is required in many nebulizers to maintain the nebulizer in an upright position with regard to a vertical axis extending through the outlet opening through which the aerosol passes. Many nebulizers are designed to operate efficiently, providing a beneficiating aerosol only when the nebulizer is maintained in a specific orientation with regard to the exhausted aerosol or possibly the gas or air spray. It would be desirable to have a nebulizer which could operate efficiently to provide a beneficial aerosol substantially independent of the orientation of the nebulizer, or easy to orientate by the patient in a variety of beneficial operating positions, and which would also utilize substantially all of the liquid medication in the nebulizer.